Vehicle leaf spring suspension



June 21, 1955 J'. A. ROEHRIG VEHICLE LEAF SPRING SUSPENSION Filed April 29, 1952 INVENTOR. JOHN A. Roar-ms ATTORNEY United States Patent automatically shortened as the result of an increase in weight on the vehicle frame, or as the result of tensioning or straightening ofthe spring caused byroadirregularities, and for the purpose of-stitfening the spring under such conditions-so as to breakage of the end thereof.

It is known in the art to provide-a vehicle spring suspension with helper or auxiliary springs, or to provide means for automatically varying the eflfectivelength of the spring as the result of loading conditions-or road irregularities. However, conventional spring; suspenquiring radius rods or requiring shackle assemblies at both ends while others include a number of auxiliary or helper springs or parts which are relatively slidable, therefore subject to excessive wear from friction, also they are expensive to manufacture. In some'types, a solid rolling shoe is used for varying points on the leaf spring. However, sucha shoe, being rigid, detracts appreciably from the softness of the ride.

An object of my invention is to provide anovel vehicle spring suspension which embodies means for automatically shortening the effective lengthofthe springas the result of an increase in load or as the result of 'roadiirregularities, which spring comprises parts which arerelatively simple and economica to manufacture" and assemble. Y

avoid the possibility of' sions of these types have the outstanding disadvantage i of being rather complicated in construction, many rethe loadcarrying For'example, if, aheaviesloadisto be carried, such as, g

by hitchinga trailer, ailower hole connection is used in order to providewgreater initial contact between arcuate A further'object of my invention is to provide, in a I vehicle springsuspension, a shackle linkage means at-thc endof the leaf spring, which linkage includes a yieldable rolling member fornot only shortening the length of the spring but for contributing itsvyieldabilityt-as a helper element or auxiliary spring in responseftov loading' of the vehicle frame or rebound from'sroad irregu larities.

Other objects and advantageszofthe present-invention will become apparent from a study of; the:following description takenwith the accompanyingtdra'wing' wherein:

Figure lis a side elevation of a: spring suspension for the rear wheels of an automobileand embodyingthe:

principles of my invention; 7 a V l Figure 2 is an enlarged fragmentary view more clearly showing the, novel features of the shackle-mounting, in Figure 1, and

Figure 3 is an enlarged fragmentary viewofra modi'-- fied form or"- adjustable link whichcan be: substituted for link-.17 shown in Figures land 2.-

Referring more particularly to Figures :1" and 2 0f: thedrawing, numeral 1 denotes. a: frame: portion at the rear; part of v'ehicle-havinga rigidly "attached thereunderneath a spring supporting .brack'etor hanger:2 =consistingofapair of spaced parallel flanges -between-whichextends a pivotal pin or bolt 3 for supporting the for-.-

ward endof a multi-leaf spring 4. The direction H the front end of the vehicle is indicated by. the-arrow. The leaves of the 'spring are..held. together 'and the. central portion of, the ,spring4 .is .mounted-= one the rear axle 5 by means of'U bolts orclips-fi-and bracket 6a whichare rigidly held together by; tightening. of' nuts 7. Underneath the rear: portion of frame l iisyri'gidly secureda ,complishing the same 2 V bracket 8 similar to. bracket 2 and through'which exe tends a bolt 9-for pivotally mounting thekupper endaoft a shacklelt). Shackle; 10 may: beabout,; /2"shorter: than a conventional shackle. The lower end of -the; shackleF10 is pivotallyqmounted'by pin orrbolt; 11 to,

the rear end portion of the longest and uppermost leaf;-

of spring 4.

An'important, feature ofmy invention resides in the" construction and, operation of theshackle; linkag which:

in, shape, as shown in Figure-,1, andhaying a radius: substantially sm aller-r than that of the; top leaflso-that? only the portion thereofadjacentbolt -11, :;is in} contact;

with the upper surface of the topleaf in spring 4; "The? rearmost end of the arcuatespring 12whichis;denoted;

by numeral. 12b is inthe form'of a partialfsloop or, eye;

which encirclesjonly af part of -bolt1 1, whereas the 1 for] I ward end portion 12a forms a completetloop about 'az bolt13a Bolt 13 pivotally connects the forward end: of

arcuate spring 12-to the, pper end v,o'f ashackle or linlc.

14, the lower end: of vwhich is pivotally connected'by-the. pinor boltlS. to a, link v16. The upperend} ofJlink-RIG; is pivotally. connected to the bolt orpin 1 1. -'A link; 17, is .i-provided, whichahas its; upper-{end pivotallyecon nccted to bolt;t9 and] a, lower portion pivota1ly'con, nected-to an intermediatepart-of, 1ink.,16-by means of; 1

a bolt 19. By'providinga'plurality of holes 19 in; thelink 18, the eifec'tivelength ofrlink 18 may be varied,v that is, the portion ,of the length of link 18rbetween its. upper pivotal end andits point of connection tolink, 16' maybe :varied, by selectively inserting bolt through:

any of thefholes 19, depending onloading: conditions.

spring I 12 and the iupper:1eaf;,.

It should be noted thatQshackIesIO and l4 -and links l6 and 17 are each formed of two spaced parallel elc-- ments, oneon each side, of spring 4.

7 Figure 3 shows; a modification of an. adjustableslink may be substituted for.link, 17-in;Figure12., As,v shown in Figure, 3, jthe link is ,,in the formofia pair, of op; a

which positely threaded elements 1'Ia and, ITIbrWh se threaded,

portions are screw-threadedly connected ,to la; turnbuckle". Thus, upon turningioflhfi. turnbuckle in one direc-g tion, the link'17a, 17b,,1,7c,is .shortened'and by turning it in an opposite direction, it is lengthened, thus ac.-

in Figure 2. a

The operation of the spring suspensionfiescribed here,- inabove is as follows Assume, that, the vehicle is lightly loaded or, that. the springt hasr -not become appreciably. t tensioned'due either to loading or; to an obstacleiencoun tteredby the wheels; 7

through agsubstantially smaller, radius than the uppermost:

e frof pr nd con a t n l1 h pp)e l y. tt et extreme rearward endportion adjacent bolt111 With the, shackle linkage in leafjof spring 4 c0mes into play. For all intentandpurposes, the spring arcuate spring 12, that is, as ifionly the conventional shackle IO-were provide, I

7 However, as-thresult of an increase of'loadingofa v'ehiclefor of-hitting; ofan obstruction by the rear wheels WhicllvWOllld tend: to' bringframe l and leaf lsp ring 4*:

closer: togetherand to:tensionand*-straighte" ut leavesarofz'spring 4; the- 'shackle' linhagevparts will J r i includes aniauxiliaryspring 12 which is normally arcuater' H purposeas selectively inserting bolt 19' in any of the holes 18 in the7 modification shown Thev rel'at-ive positio oflh h ckle, linkage will" be as; shown'in Figure l or asshownsin dotted; lines'in Figure2, that'is, with the arcuate spfring12 curvedh s," po i ionla y so t r e. i -pm; vided since-,substantiallythe entire lengthof the upper.

suspension 'would act practically, the. same as if'links 14, 16 and'17 wereomitted together with tually assume the position shown in full lines in Figure 2, that is, shackle will assume a smaller angle relative to frame 1 and arcuate spring 12 will roll out to an arc of increased diameter and approaching the arc of the upper leaf of spring 4. Two highly important results are obtained from this action. The first is that by virtue of the rolling-like movement of spring 12 as it moves from the position shown in Figure l to that shown in Figure 2 (or from the dotted to the full line position shown in Figure 2), a greater length of the rearmost end portion of the upper leaf is contacted thereby shortening the effective length of spring 4 and thereby increasing its stiffness. Secondly, the increase in radius of spring 12 will greatly increase this action, thus will eliminate the possibility of breakage of the end of the upper leaf of spring 4 which is a relatively weak point. Upon removal of the additional load on the frame, the arcuate spring will roll back to its initial posit-ion and will assume a smaller radius, thereby contacting very little of the upper end portion of the top leaf of spring 4 and thus allowing the top leaf to come into play throughout its entire length giving more flexibility and a softer ride.

It will be seen, therefore, that the action of the spring 4 as influenced by arcuate element 12 and the shackle linkage arrangement is to move the load bearing point in a direction towards the center of the spring as the result of additional loading of the frame or as the result of rebound of the rear wheels from a road obstacle, and vice versa, that is, to move the load bearing point towards the end of the spring by rolling and winding of spring 12 caused by removal of the additional load, or movement away of the spring 4 from the frame following tensioning or straightening of spring 4. Thus, the effective length of the spring is shortened at times of heavy loading of the frame so as to increase stiffness, and is lengthened upon removal of such load to allow the entire length of the upper leaf to come into play and to give a softer ride.

While the vehicle spring suspension has been described as being applicable to a rear wheel suspension, it will be apparent that it is also useful for a front wheel suspension.

Although a single linkage, including an arcuate spring is shown at the rear end of the spring 4, it will be apparent that, if desired, two such linkages as well as two such arcuate members may be used instead, one at each end of the spring 4, in which case, the forward linkage will be the reverse of the rear linkage. That is to say, shackles 14 will be closer together than shackles 10.

It will also be apparent that if the additional resilience provided by arcuate spring 12 is not needed as a helper spring, it may be made of stiff material which will not reduce in radius as the result of loading and will merely roll on the upper leaf to change the effective length thereof in response to loading.

Thus it will be seen that I have provided an efficient and relatively simple vehicle'spring suspension which will automatically vary the length of the spring in response to loading or rebound from road irregularities in order to increase the stiffness of the spring in response to heavy loading and thus prevent the possibility of breakage at the weakest point, namely, the end of the upper leaf, and to allow the full length of the upper leaf to come intoplay at the moment the additional loading is removed so as to increase the resilience of the spring and the softness of the ride; furthermore, I have provided a spring suspension which greatly stabilizes a car, particularly when travelling around bends, thus being a great aid to knee action cars, particularly, which have a tendency to become unstable around bends; furthermore, I have provided a shackle means for a vehicle spring suspension with means for initially varying the degree of stiffness of the spring or the softeness of the ride by mere adjustment of the length of one of the links thereof, thereby making the spring suitable for Widely different loads,

4 therefore being particularly suitable for vehicle suspensions for trailers, semi-trailers and trucks.

While I have illustrated and described several embodiments of my invention, it will be understood that these are by way of illustration only, and that various changes and modifications may be made within the contemplation of my invention and within the scope of the following claims.

I claim: 1. A vehicle spring suspension comprising a multi-leaf spring for supporting an axle substantially centrally thereof, one end of said spring being pivotally mounted directly to the frame of the vehicle and the other end including shackle means connected to a longitudinally spaced point on said frame, said shackle means including a link whose endsare pivotally connected to the end of I said spring and to said frame, an arcuate element of shorter radius than the spring and having one end supported on the top of one end portion of the spring and pivotally connected thereto, said arcuate member having a rolling movement on said end portion of the spring, said shackle means also including a link pivotally connected to the other end of said arcuate element, and a second link pivotally connected to the other end of said last mentioned link and to said first mentioned pivotally connected end of said spring, and a third link for connecting an intermediate portion of said second link to said frame, whereby roll'mg moving of said arcuate element takes place on said end portion of the spring as the result of loading of said frame to shorten the effective length of said spring.

2. A vehicle suspension as recited in claim 1 wherein said arcuate element is in the form of a leaf spring whose radius increases so as to contact a greater length of said spring end portion as the result of loading of said frame.

3. A vehicle suspension as recited in claim 1 wherein said third link includes means for adjusting the length thereof between the point of connection to the frame and the point of connection to said second link.

4. A vehicle spring suspension comprising a leaf spring, a shackle linkage for connecting one end of said spring to the frame of a vehicle, said shackle linkage comprising a shackle element pivotally connected to the said spring end and to said frame, an arcuate element having an end portion partially encircling the pivotal connection between said shackle and spring end, a second shackleelement having one end pivotally connected to the other end of said arcuate element, a link connecting the other end of said second shackle and to the said pivotal connection at the end of said spring, and a second link pivotally mounted at one end to the upper end of said first shackle and at its lower end to an intermediate portion of said first link, said arcuate element having a rolling movement on the top end portion of said spring adjacent said first shackle so as to displace the load bearing point and shorten the effective length of said spring in response to increase in loading to increase its stiffness. g

5. Apparatus recited in claim 4 wherein said arcuate element is in the form of a leaf spring of substantially shorter radius than the uppermost leaf of said vehicle spring so that upon loading of said frame or upon compression of said spring, the radius of said arcuate element will increase, thus increasing thelength of contact between. said arcuate element and the upper end portion of said spring, and wherein said second link is of adjustable length for initially varying the length of contact between said arcuate element and said upper end portion of said spring.

References Cited in the file of this patent UNITED STATES PATENTS Germany Dec. 12, 1927 

